I am totally unsure what is right and not. I reported the issue
upstream
and they answerd me this [1]:
"@martinkg, the Qt library requires the language and country to be
separated by a hyphen rather than an underscore:
https://wiki.qt.io/Basics_of_Locales
Olive does not recognize translation files renamed with underscore."
Means this, that the macro %find_lang can't handle transation files with
underscrore ?
No, it means that their application (Olive) cannot handle them. IMHO, the
application is broken and needs to be fixed: